A box contains 6 red balls, 4 blue balls, and 2 green balls. Three balls are randomly drawn (without replacement) from the box. What is the probability that the three balls selected are all the same color?

follow the basic methodology that Drwls showed you in the previous post. Assume each color ball can be distinguished from each other. (e.g., name the green balls g1 and g2) First, the denominator. How many different ways can 3 balls from 12 be chosen. 12-choose-3 is 12!/3!(12-3)!

Now the numerator. How many different ways can 3 red balls be chosen from 6? Plus how many different ways can 3 blue balls be chosen from 4.